There wouldn't be any benefits a large sand area would provide that a standard sand bath wouldn't
Furthermore,with a large area of sand you're introducing more of a potential for dust to enter the habitat,which can cause respiratory problems and is why sand really should be kept to a minimal sand bath with just enough depth for the hamster to roll in.
However,as long as the sand is sifted and sterilized it can be used,just not for a large area!There are more enriching things out there than sand,especially all the safe things.Keep substrate throughout the cage to a safe variety(Fitch in the UK,not wood as this can and often will cause an allergic reaction and is just not worth the risk to use when there are so many perfectly good substrates that never cause allergic reactions),and add enrichment in the form of foraging toys and things like that